1. Field
The present invention relates to a pixel and an organic light emitting display using the same, and more particularly, to a pixel configured to stably compensate for a threshold voltage and an organic light emitting display using the same.
2. Description of the Related Technology
Recently, various flat panel displays (FPD) having reduced weight and volume as compared with cathode ray tubes (CRT) have been developed. The FPDs include liquid crystal displays (LCD), field emission displays (FED), plasma display panels (PDP), and organic light emitting displays.
The organic light emitting displays display images using organic light emitting diodes (OLED) that generate light through re-combination of electrons and holes. The organic light emitting display has high response speed and is driven with low power consumption.
The organic light emitting display includes a plurality of pixels arranged near intersections of a plurality of data lines, scan lines, and power supply lines in a matrix. Each of the pixels commonly includes an organic light emitting diode (OLED), at least two transistors including a driving transistor, and at least one capacitor.
The organic light emitting display consumes low power. However, an amount of current that flows to organic light emitting diodes (OLED) changes in accordance with a deviation in the threshold voltages of the driving transistors included in the pixels so that non-uniformity in display is caused. That is, the characteristics of the driving transistors change in accordance with the manufacturing process variation of the driving transistors included in the pixels. Generally, it is not possible to manufacture all of the transistors of the organic light emitting display to have the same characteristic in current manufacturing processes. Therefore, a deviation in the threshold voltages of the driving transistors is generated.
In order to solve the problem, a method of adding a compensating circuit formed of a plurality of transistors and a capacitor to each of the pixels is suggested. The compensating circuits couple the driving transistors in the form of a diode in a period where scan signals are supplied to compensate for the deviation in the threshold voltages of the driving transistors.
On the other hand, recently, a method of driving a panel at high resolution and/or high driving frequency in order to improve picture quality is suggested. However, when the panel is driven at high resolution and/or high driving frequency, time of the scan signals is reduced so that it is not possible to compensate for the threshold voltages of the driving transistors.